Chemical Engineering December 2017 - 46

This method more than doubles the
amount of C18:0 in the hydrogenated
oil. The excess levels of the
C18:0 are to be removed via fractional
crystallization.
Evaluation of Option 1. After reviewing
the bench-scale data from the catalyst
and reaction experiments and talking with
the engineers who did the work, the engineer
verifies that the hydrogenation will
reliably produce the desired composition
for Product X. The synthesis engineer also
estimates the optimization of the ratio of
the metals and of the particle size have a
95+% probability of success and deems
this option feasible.
Evaluation of Option 2. By talking with
company engineers who have fractional
crystallization experience, the synthesis
engineer quickly confirms that the C18:0
can be crystallized while leaving the
C18:1, C18:2, and C18:3 oils in solution.
He or she also concludes the C16:0 will
crystallize with the C18:0. Thus, during
crystal separation both will be removed
from the liquid oil. As well, he or she finds
separating C16:0 from C18:0 from is not
practical since their melting points are
too close to each other. After the crystal
removal step, the engineer calculates the
oil would have the following composition:
* C16:0 <1%
* C18:0 <1%
* C18:1 88%
* C18:2 10%
* C18:3 <0.2%
Since the Option 2 product contains no
C16:0, it does not meet the desired composition
for Product X. (Olive oil contains
about 13% C16:0.) Although the oil without
the C16:0 would be deemed healthy,
it could not be marketed as an olive oil
substitute. Therefore, it is eliminated.
Conclusion: Only Option 1 is technically
feasible. Option 2 will be dropped
from further consideration.
Examples 4 and 5 can be found in the
online version of this article (see link, left).
SUMMARY
Use of the Process Synthesis Model will
result in better designs and lower R&D,
capital, and operating costs. The model
A longer version of this article, which
includes additional tables and examples,
can be found in the online version of this
article at www.chemengonline.com
46
has the following three phases:
* Setting business and technical objectives
before synthesis begins.
* Creating and investigating a more
thorough and complete set of design
options than is typical. This increases
the odds of finding more elegant solutions
to any design problem. The
Process Synthesis Model uses three
tools to assist with option creation: the
Technical Function Flowsheet, Probing
Questions and Unit Operations Guides
* Assessing options. One first evaluates
options technically and eliminates
those that do not meet all of the quality,
HSE, and business requirements. If
there is more than one technically acceptable
option, one uses economics
to determine which is the best option n
Edited by Gerald Ondrey
Author
Thane Brown (Email: trbnjb@earthlink.
net) worked for more than 36 years for
Procter & Gamble in a variety of engineering
and manufacturing roles, primarily
in the food-and-beverage business
and in health,
safety and
environmental engineering. In his last
position there, Brown was director of
North American engineering. After retiring,
he taught engineering economics at
the University of Cincinnati, and plant design at the University of
Dayton. Brown is presently a member of the Chemical Engineering
Advisory Committees at the University of Dayton, at
Miami University (Oxford, Ohio), at the University of Louisville
and at the University of Cincinnati. He also works as a SCORE
counselor, providing free assistance to small businesses in the
Cincinnati area. Brown authored the book " Engineering Economics
and Economic Design for Process Engineers " [6], as
well as a number of articles on engineering economics, batch
pressure filtration and heat transfer. He is a registered professional
engineer in Ohio (inactive), and holds a B.S.Ch.E. from
Oregon State University.
References
1. Tullo, A.H., Global Top 50 Chemical Companies, Chem. & Eng. News,
July 27, 2015, pp. 14-17.
2. Cussler, E. and Moggridge, G.D., " Chemical Product Design, " Cambridge
University Press, U.K., 2001.
3. Brown, T.R. and Singh, S., Project Optimization through Engineering,
Chem. Eng. July 2014, p. 51.
4. Heath, C. and Heath, D., " Decisive, " Crown Publishing Group, New York,
2013.
5. Brown, T.R., Capital and Production Costs: Improving the Bottom Line,
Chem. Eng. January 2010, p. 26.
6. Brown, T.R., " Engineering Economics and Economic Design for Process
Engineers, " CRC Press, 2007, p. 201.
7. Smith, R., " Chemical Process Design and Integration, " John Wiley and
Sons, 2005, p. 9.
8. Ref. 6, pp. 151-152.
9. Murphy, R.M., " Introduction to Chemical Processes: Principles, Analysis,
Synthesis, " McGraw Hill, New York, 2005, pp. 121-137.
10. Ulman, D.G., " The Mechanical Design Process, " McGraw Hill, New York,
1997, pp. 147-148.
11. Smith, R., " Chemical Process Design, " McGraw Hill, New York, 1995,
pp. 3-8.
12. Douglas, J.M., " Conceptual Design of Chemical Processes, " McGrawHill,
1988.
13. Turton, R., others, " Analysis, Synthesis, and Design of Chemical Processes, "
4th Edition, Prentice Hall PTR, 2012.
14. Peters, M.S., Timmerhaus, K.D., and West, R.E., " Plant Design and
Economics for Chemical Engineers, " McGraw Hill, New York, 2003.
15. Perry, R.H. and Green, D.W., 7th Edition, " Perry's Chemical Engineering
Handbook, " McGraw Hill, New York, 1997.
16. Seider, W.D., others, " Product and Process Design Principles Synthesis,
Analysis, and Evaluation, " 3rd Edition, John Wiley & Sons, 2009.
17. Kleppmann, W. Optimizing Products and Process Efficiently, Chem.
Eng., November 2014.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
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